page_title: Apollo (spacecraft)
section_title: Launch escape system (LES)
hierarchical_section_title: Apollo (spacecraft) / Launch escape system (LES)
caption_attribution_description: Apollo Pad Abort Test #2, pitch motor and launch escape motor firing
context_page_description: The Apollo spacecraft was composed of three parts designed to accomplish the American Apollo program's goal of landing astronauts on the Moon by the end of the 1960s and returning them safely to Earth. The expendable spacecraft consisted of a combined command and service module and an Apollo Lunar Module. Two additional components complemented the spacecraft stack for space vehicle assembly: a spacecraft–LM adapter designed to shield the LM from the aerodynamic stress of launch and to connect the CSM to the Saturn launch vehicle and a launch escape system to carry the crew in the command module safely away from the launch vehicle in the event of a launch emergency.
  The design was based on the lunar orbit rendezvous approach: two docked spacecraft were sent to the Moon and went into lunar orbit. While the LM separated and landed, the CSM remained in orbit. After the lunar excursion, the two craft rendezvoused and docked in lunar orbit, and the CSM returned the crew to Earth. The command module was the only part of the space vehicle that returned with the crew to the Earth's surface.
context_section_description: The Apollo launch escape system (LES) was built by the Lockheed Propulsion Company. Its purpose was to abort the mission by pulling the CM (the crew cabin) away from the launch vehicle in an emergency, such as a pad fire before launch, guidance failure, or launch vehicle failure likely to lead to an imminent explosion.
  The LES included three wires that ran down the exterior of the launch vehicle. If the signals from any two of the wires were lost, the LES would activate automatically. Alternatively, the Commander could activate the system manually using one of two translation controller handles, which were switched to a special abort mode for launch. When activated, the LES would fire a solid fuel escape rocket and open a canard system to direct the CM away from, and off the path of, a launch vehicle in trouble. The LES would then jettison and the CM would land with its parachute recovery system.
  If the emergency happened on the launch pad, the LES would lift the CM to a sufficient height to allow the recovery parachutes to deploy safely before coming in contact with the ground.
  In the absence of an emergency, the LES was routinely jettisoned about 20 or 30 seconds after the launch vehicle's second-stage ignition, using a separate solid-fuel rocket motor manufactured by the Thiokol Chemical Company. Abort modes after this point would be accomplished without the LES. The LES was carried but never used on four uncrewed Apollo flights, and fifteen crewed Apollo, Skylab, and Apollo-Soyuz Test Project flights.
caption: Pad abort test (2), showing pitch motor and launch escape motor in operation
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